import os
import time
source = [r'F:\pythonStudy\struct', r'E:\2013-07-22']
target_dir = "E:\\" 
target = target_dir + time.strftime('%Y%m%d%H%M%S') + '.rar'
rar_command = r'"C:\Program Files (x86)\WinRAR\Rar.exe" a %s %s'  %(target,' '.join(source))
if os.system(rar_command) == 0:
    print 'Successful backup to', target
else:
    print 'Backup FAILED'